User`s manual

4.4 Flash ROM (System ROM)
4.4.2 Flash ROM Structure
During the power-up and initialization sequence, the AlphaPC64 always loads
the first image if the BOOT_OPTION jumper J3-25/26 is not installed. Then
the first image (the debug monitor) will be booted.
If jumper J3-25/26 is installed, the AlphaPC64 reads the value at location 3F
of the TOY NVRAM. The AlphaPC64 uses the value found there to determine
which image will be selected (see Table 4–3). The selected image is loaded and
executed.
Table 4–3 Higher 512KB Flash ROM Image Selection
TOY RAM Value
1
Firmware ID
2
Image Description
00 0 Evaluation board debug monitor firmware
01 1 Windows NT ARC firmware
02 2 Alpha SRM firmware (OpenVMS)
3
03 2 Alpha SRM firmware (Digital UNIX)
3
8n NA
4
SROM code will load the nth image from
flash ROM.
If n=0, the SROM code loads the entire
flash ROM contents.
If n=1, 2, ..., the SROM code loads the first
image, second image, and so on.
1
Operating system type. Found at TOY RAM address 3F.
2
Found in image header.
3
Note: SRM firmware is not included in the AlphaPC64 kit.
The flash ROM contains only one of these images.
4
Not applicable.
If an image is specified and is not found, the AlphaPC64 loads the first image
in the flash ROM with a valid header. If no valid header is found, the entire
1MB flash image is loaded at address 0000 0000.
The following sequence of steps describes how to change the value stored in
TOY RAM location 3F by using either the basic debug monitor commands or
the debug monitor bootopt command.
4–12 Functional Elements